Basic Antenna / Reception Questions

[Mobilman44]

Hi!
I'm pretty new to the world of radios and scanners so please go easy on me.......

I want a better antenna for my portable Uniden 436, but have gotten confused with specs and such.

It appears that the transmissions I'm interested in are in the 400 and 800 MHZ range.

So, if I get an "800 MHz" antenna, will it also improve on the 400 MHz listening? Or do I need two antennas for optimal reception.

And lastly, would a 6dba be "better" than say a 2 dba?

Your help will be greatly appreciated!

 

[CQ]

Is it a handheld antenna or base?

Here are some candidates
https://www.universal-radio.com/catalog/scanants/5458.html
https://www.universal-radio.com/catalog/scanants/2368.html
https://www.universal-radio.com/catalog/scanants/5440.html

Here's some information to digest for antenna gain which benefits transmitters more.
Antenna Gain

 

[I_am_Alpha1]

Hi!
I'm pretty new to the world of radios and scanners so please go easy on me.......

I want a better antenna for my portable Uniden 436, but have gotten confused with specs and such.

It appears that the transmissions I'm interested in are in the 400 and 800 MHZ range.

So, if I get an "800 MHz" antenna, will it also improve on the 400 MHz listening? Or do I need two antennas for optimal reception.

And lastly, would a 6dba be "better" than say a 2 dba?

Your help will be greatly appreciated!

There is plenty of antenna info on RR...some good, some bad. In reality it's difficult to answer your question. Antenna performance varies greatly...topography, location, type of system, orientation of scanner are just a few of the variables. What works for one may be a dud for you. Some basics about antennas--they have a wide receive capability (I have one that does 25 MhZ to 1 GhZ). Don't expect a huge difference between the stock antenna and top of the line antennas--some increase, but not huge. You would get greater performance using an outside antenna--defeating the purpose of the 436. Antenna gain is referring to its transmit capability--nothing to do with receive. If you are not happy with the performance of the stock antenna, try Diamond or Nagoya and see if they help--you may have to do this a few times until you are happy. Of course a better antenna is not going to help you if you are having issues with simulcast...in that case, you are better off dumbing down the antenna.

 

[W8RMH]

The best aftermarket scanner antenna I have ever used is the 1.75 inch Comet CH-32 Miracle Baby. I bought one back in the early nineties for use on my 460 MHz PS system. It worked great on VHF as well as the new 800 MHz systems coming out. I also used it to transmit on a Yaesu FT60R and a Baofeng. I recently purchased a second one to replace the older one that I sold with a scanner. It was 20+ years old and still going strong.

Manufactured for amateur dual band (144-148 & 430-450 MHz) it also has an extended receive range of 118-160 MHz, 250-290 MHz, 360-390 MHz, 420-470 MHz, 820-960 MHz, 1260-1300 MHz. and works better on simulcast than any other portable antenna.

 

[jonwienke]

Miracle Baby is ONLY useful in simulcast situations where signal attenuation may be helpful decoding LSM. For every other application they reduce usable range in direct proportion to their reduced size.

 

[Mobilman44]

Hi, and thanks all for the input.........
Like hats, "one size fits all" just doesn't seem to apply with antennas. I will obviously need to experiment, and may start with the Diamond RH77CA.

I asked this earlier and it may have been overlooked....... What does say "+6db or +2db" mean in antenna advertising? I'm thinking the answer may be obvious but maybe not.

Thanks all!

 

[nd5y]

. Antenna gain is referring to its transmit capability--nothing to do with receive.

This is wrong. Antenna gain is the same for both receiving and transmitting.

 

[jackj]

Tom is right. Also antenna gain comes at the expense of omni directional coverage. You take the signal that is wasted going above and below the horizon and squish it down to the horizon. Also bandwidth comes at the expense of gain. The reverse is also true, narrowing the bandwidth will enable increased gain.

In short, antenna design is a series of compromises.

 

[krokus]

I asked this earlier and it may have been overlooked....... What does say "+6db or +2db" mean in antenna advertising? I'm thinking the answer may be obvious but maybe not.

dBi would be in reference to an imaginary isotropic antenna. dBa is indicating some type of reference, but I'm not sure what. The +2dB means that antenna has about 1.2 times the signal, and the +6dB has twice the signal.

This Wiki page has more info than you probably want.

https://en.m.wikipedia.org/wiki/Decibel

Sent using Tapatalk

 

[iMONITOR]

The best aftermarket scanner antenna I have ever used is the 1.75 inch Comet CH-32 Miracle Baby.



Manufactured for amateur dual band (144-148 & 430-450 MHz) it also has an extended receive range of 118-160 MHz, 250-290 MHz, 360-390 MHz, 420-470 MHz, 820-960 MHz, 1260-1300 MHz. and works better on simulcast than any other portable antenna.

+1 I've been using them for over a decade. Very compact, and sturdy for hand-helds, and I even use on on my BCD536HP in my office! I'm constantly impressed how well it works and recommend them frequently.

 

[iMONITOR]

Hi, and thanks all for the input.........
Like hats, "one size fits all" just doesn't seem to apply with antennas. I will obviously need to experiment, and may start with the Diamond RH77CA.

The RH77CA performs great for me on the150/450 bands and very well on commercial/military aircraft bands. However I find it's lacking on the 700-800 bands.

The best portable antenna for 700-800 I've found to be the discontinued Radio Shack RS-800, and now it's equivalent, by Remtronics:

REMTRONIX 800 MHz Portable BNC Antenna | Scanner Master

I use one of those when not using the CH-32 Miracle Baby, typically while traveling in Northern Michigan.

 

[KB4MSZ]

Optimize the Coverage

If you wish to optimize the coverage of the 400 and 800 MHz bands then you might wish to possibly use a diplexer. Through a coaxial feed from your scanner, a diplexer will give you separate outputs for the two bands you mentioned. I just installed such a diplexer for my mobile ham station, giving me monoband (single purpose) antennas for both the 440 MHz ham band and the 800 MHz public service frequencies. The unit I used is the Comet NCG CF-413B diplexer. It of course has a tiny insertion loss but the dedicated antennas it allows on each band way more than make up for this. You will need the adapters for the N and SO239 connectors it uses to connect to your antennas, as well as between your scanner and the diplexer.

 

[spacellamaman]

RS800- next topic

get one or more "REMTRONIX 800 MHz Portable BNC Antenna" and you can call it a day. i believe they were the OEM for the Radio Shack 800s, which i have a buttload of and have used to death for bout 4-5 years now. they are hard to beat, down to 225mhz, if antenna height is same, coke/pepsi challenge shows it to beat all comers. there are very few products that recieve such praise from me.

have one that was run over by a 18 wheeler, while attached to my dear departed BC346XT, and mangled the outer BNC part, and crinkled the rest of it nicely. inner BNC part was not damaged, so i taped it inplace to a double female BNC connector, hooked to a BNC jumper cable, and it now resides, suction-cupped to my rear window and does right nicely.